Comparative study of scatter-related visual quality after FS-SBK, SBK and SMILE refractive surgeries

Abstract

Objective To investigate the influence of FS-SBK,SBK,and SMILE refractive surgeries on visual quality by analyzing variations in the glare index and the visual quality parameters of distinct refractive errors.Methods In this prosective cases control study,122 patients,who underwent SBK,FS-SBK or SMILE surgery,were enrolled from August to October 2013 and divided into high,moderate and low myopia groups.The glare index (opposite sector index,OSI) and modulation transfer function cut-off (MTF cut-off) were measured with a OQAS visual quality analyzing system preoperatively and one day,one week and one month postoperatively.Additional measurements were made to evaluate the differences among the three surgical methods.Results The effects on postoperative visual quality due to the different surgical procedures were as follows:①Vision:visual acuity improved after all surgeries and there were no significant differences among the results.②OSI:there was no statistically significant difference between SBK and FS-SBK.When compared with pre-operative OSI,there was a statistically significant difference between moderate and high myopia groups one week after SMILE surgery.③MTF cut-off:there were no statistically significant differences before and after surgery in the FS-SBK group,but there was a statistically significant difference from both SBK and SMILE surgeries in the moderate myopia group 1 week postoperatively compared with the preoperative period and 1 month postoperatively.However,there were no significant differences for the remaining time points.No significant differences were found between the different myopia groups.Conclusion Postoperative visual quality improves after the three surgical procedures discussed above.Due to a raised OSI after SMILE surgery,LASIK is the better option for high and moderate degrees of myopia.While the MTF cut-off did not vary significantly between pre-and postoperative FS-SBK,it decreased one week later after SBK and SMILE surgeries but recovered after one month in the moderate myopia group,even reverting to pre-operative levels. Key words: Femtosecond laser; Small incision lenticule extraction; Keratomileusis,sub-Bowman; Opposite sector index; Modulation transfer function cut-off; Visual quality